大约有 40,000 项符合查询结果（耗时：0.0306秒） [XML]
How do I find which transaction is causing a “Waiting for table metadata lock” state?
...ransactions waiting for locks:
SELECT TRX_ID, TRX_REQUESTED_LOCK_ID, TRX_MYSQL_THREAD_ID, TRX_QUERY
FROM INNODB_TRX
WHERE TRX_STATE = 'LOCK WAIT';
Reference - MySQL Troubleshooting: What To Do When Queries Don't Work, Chapter 6 - Page 96.
...
Detect if Visual C++ Redistributable for Visual Studio 2012 is installed
...been finalized, yet. As I'm guessing the upper-most keys of:
[HKEY_CLASSES_ROOT\Installer\Dependencies\,,amd64,14.0,bundle]
and
[HKEY_CLASSES_ROOT\Installer\Dependencies\,,x86,14.0,bundle]
are subject to change, or at least have different nested GUIDs, I'm going to use list the key that ends with a...
ALTER TABLE without locking the table?
When doing an ALTER TABLE statement in MySQL, the whole table is read-locked (allowing concurrent reads, but prohibiting concurrent writes) for the duration of the statement. If it's a big table, INSERT or UPDATE statements could be blocked for a looooong time. Is there a way to do a "hot alter", li...
Python ElementTree module: How to ignore the namespace of XML files to locate matching element when
...}')
if has_namespace:
el.tag = postfix # strip all namespaces
root = it.root
This is based on the discussion here:
http://bugs.python.org/issue18304
Update: rpartition instead of partition makes sure you get the tag name in postfix even if there is no namespace. Thus you could conden...
Find running median from a stream of integers
...Add next item to one of the heaps
if next item is smaller than maxHeap root add it to maxHeap,
else add it to minHeap
Step 2: Balance the heaps (after this step heaps will be either balanced or
one of them will contain 1 more item)
if number of elements in one of the heaps is greater ...
Python class inherits object
...
Calling the root class object isn't all that confusing, and in fact it's pretty standard. Smalltalk has a root class named Object, and a root metaclass named Class. Why? Because, just as Dog is a class for dogs, Object is a class for obj...
What are the applications of binary trees?
...hing when you balance them. This involves rotating sub-trees through their root node so that the height difference between any two sub-trees is less than or equal to 1. Adding those names above one at a time into a balanced tree would give you the following sequence:
1. Alice
/ \
= ...
Installing in Homebrew errors
...ething installed via homebrew that requires special user permissions, like mysql, make sure to give those permissions back (as the above command gives recursive ownership to everything inside /usr/local to you ($USER). In the case of mysql, it's…
sudo chown -RL mysql:mysql /usr/local/mysql/dat...
Unable to import a module that is definitely installed
... my case, it is permission problem. The package was somehow installed with root rw permission only, other user just cannot rw to it!
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内存优化总结:ptmalloc、tcmalloc和jemalloc - 操作系统(内核) - 清泛网 - ...
...，tcmalloc性能上也有明显的优势，并且相对平稳。
github mysql优化
github使用tcmalloc后，mysql性能提升30%
Jemalloc
jemalloc是facebook推出的， 最早的时候是freebsd的libc malloc实现。 目前在firefox、facebook服务器各种组件中大量使用。
jemall...